What is TOPCon technology?

TOPCon technology belongs to the N-type cells. P-type and N-type solar cells are made from a silicon wafer. The silicon wafer is doped with chemicals to improve electricity production, the difference between N-type and P-type comes from the material used to dope it. P-type cells are doped with boron, while N-type cells are doped with phosphorus. The advantage of phosphorus against boron is that boron can be subjected to degradation because of oxygen, which is not the case for phosphorus. In addition, phosphorus doping adds free electrons to the wafer, which increases efficiency.

N-type cells are divided into PERT, Topcon, HJT, and IBC. TOPCon (Tunnel Oxide Passivated Contact) cells are the main representative. They have been first introduced in 2013, but have been adopted by manufacturers only since 2019.

Figure 1 â€“ PERC cell & TOPCon cell architecture (source: rena.com)

To manufacture TOPCon cells, tunnel oxide, and polysilicon layers are added to the rear side of the cell. It helps the cell handle higher voltages, which increases power production.

What are the advantages of TOPCon technology?

Manufacturing process

TOPCon modules can be manufactured with the same machines as P-type modules, which means the adoption of TOPCon cells doesnâ€™t require high capital investment for manufacturers.

Higher efficiency

TOPCon cells convert more sunlight that P-type cells, which results in a higher cell and module efficiency. TOPCon cells can reach 28% efficiency (the PERC cell maximum efficiency is around 24%).

Lower degradation

TOPCon modules have a lower power degradation power during the 1st year and during the 30 years of PV panels use, compared to PERC panels.

Lower temperature coefficient

The temperature coefficient is the percentage of power output lost by a solar panel for each degree of temperature increase. It impacts the power generation of PV modules in hot conditions.

TOPCon cells have a better resistance to high temperatures, which means the efficiency of TOPCon modules will be higher in hot climates compared to PERC modules.

Bifaciality rate

TOPCon cells have a better power increase in bifacial modules than PERC modules. It is an important factor as bifacial solar modules are getting more and more popular on the market.

Low light performance

TOPcon modules have a higher efficiency in low light condition, which extends the electricity generation period during the day and improve the performance of the installation over time.

Market outlook of TOPCon technology

Figure 2 â€“ World market share of PERC/PERL/PERT/TOPCon technology (Source: researchgate.net)

According to studies, The global TOPCon cell market will grow from USD 7354.76 million in 2021 to USD 24837.68 million in 2027 (CAGR of 22.49%).

In terms of market share, it can be expected that the TOPCon world market share will grow from 8% in 2020 to 50% in 2031. But the China Photovoltaic Industry Association (CPIA) has stated that TOPCon technology could take the lead as early as 2024.